5 Medieval Castle Aquarium Decor Ideas You Can Copy

Besides being classic aquarium decorations, castles add an element of fun to your tank for fish that like to swim through or hide behind things in their habitat. It can also help make a calmer aquarium since it can become a place to hide for shy fish. And if your bully fish decides that he’s the king of the castle, he’ll leave everyone else alone for once.

There are a lot of castle aquarium decor options, but I have some unconventional ideas for you to consider. One features a classic wizard castle, but the others take the forms of Roman palace ruins, a palatial Cambodian temple, and hints of castles that once existed.


Top 5 Castle Aquarium Decorations to Choose From

My top five castle aquarium ideas may be a little surprising because, while some are complete structures, others are in ruins and hint at a palace that once existed in a kingdom long ago and far away.

Wizard’s Castle

Penn-Plax Wizard’s Castle Aquarium Decoration Hand Painted With Realistic Details 10 Inches High, Multi-Color (RRW8), 1 Count (Pack of 1)
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Is it just me, or does the Wizard’s Castle look a bit like Hogwarts? If you’re a Harry Potter fan, this might be the castle for you.

Your fish are going to love this castle. It has entrances on the front and back and a swim-through area. I like that it has several entrance levels so that several fish can play inside all at once. Also, all the turrets make great places for nocturnal fish to hide during the day.

If you’re trying to decide if it will fit in your aquarium, keep the size in mind. This decoration is 8 inches wide, 10.2 inches high, and 6.2 inches deep. It’s going to end up sitting only a couple of inches below the rim of a lot of smaller tanks, but that’s fine if you don’t mind the turrets sticking out of the water when it evaporates by week’s end. I think it’s a neat effect myself.

Want something bigger than this? Check out these Large Aquarium Decoration ideas.

Antique Roman Column Ruins

POPETPOP Resin Aquarium Decorations-Fish Tank Decorations Antique Roman Column Ruins European Castle Ornaments Large
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If your idea of a palace looks more like Roman ruins, you’re going to love this option. I like how many columns fish have to swim in and out of these ruins.

This option is lovely when you have schooling fish. Watching a dozen or more cardinal tetras swimming through the columns simultaneously makes you think of the Lost City of Atlantis at the bottom of the sea somewhere.

The ruins also include a few plastic plants to look even more like an underwater castle seascape. However, I think it looks especially lovely with large rocks around it, more like the site of a crumbling Roman temple. Some landscaping stones that will look nice around your ruins include:

  • Dragon stone
  • Seiryu stone
  • Granite

At 4.7 x 6.2 x 5.5 inches, you can add ancient ruins to almost any sized tank.

Ancient Rock Face Castle

balacoo Aquarium Mountain View Stone Ornament Tree Rock Cave Fish Tank Decoration Fish Hiding Cave
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The ancient rock face castle is a forgotten Buddhist temple that you can imagine stumbling upon in a Cambodian jungle. Trees and jungle vines have started to envelop it. There are a few entrances, but the inside is dark and foreboding. Choosing this castle is the piece upon which to build the rest of the landscaping in your tank.

One of the most amazing things you can do with this palatial structure is to nestle it in a landscape that mimics the pitted, greenery-covered Cambodian mountains. It will look exceptionally handsome in a planted tank with rocks around.

One specific look that looks good with this temple is surrounding it with dragon stone covered in dwarf baby tears (Hemianthus callitrichoides) and Mini pearl moss (Plagiomnium affine), which will ultimately end up looking like the background of a lost world.

Besides its landscaping potential, I like the ancient rock face castle for its ability to be a safe hiding place for more shy fish. In addition, having a lower and upper area allows more than one fish to be inside comfortably simultaneously.

At 10.6 x 7 x 5.9 inches, the temple is best in tanks 20 gallons or more, as long as the height is above about 12 inches.

Rope Bridge & Castle in the Mountains

Aquatic Planet Rope Bridge Mountains Large Aquarium Ornament Decor Decoration Fish Tank (Large (16 x 4 x 7 inches))
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This rope bridge has a story to tell. The stairs once came from somewhere and led to somewhere else. I like to imagine that it was a palace. You could add a palace to the scene if you have a larger tank. However, you need to consider whether they will be in scale with each other or not.

It has areas below both stone support structures for fish to go through and shelter. Some smaller will inevitably swim through the ropes on the bridge as well. Plus, the top of the stairway offers a small blind for a fish refuge. With time, the rope on the bridge will start to disintegrate, but then it will look even more like an authentic ruin.

The bridge measures 16.14 x 3.95 x 6.89 inches. Thus, you could put it in any tank over about 5 gallons.

Dragon Skull Gazer

Penn-Plax RR1207 Dragon Skull Gazer Aquarium Ornament and Decor - Available in 2 Sizes for Any Tank, Large
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Perhaps a dragon once guarded your castle, but now only its skull is left behind. Maybe it burned the castle to the ground with its fiery breath. However, the heroes of the story slew the dragon before it could lay waste to more of the countryside.

At any rate, here the dragon skull lies. I like the idea of surrounding it with large rocks that were part of the castle it once destroyed. The same stones I listed for the roman ruins would look good with the dragon skull. Or perhaps strew about some jewel-colored rocks to be representative of the treasure it was guarding.

This dragon skull is 7.5 x 4.75 x 5 inches, so it will take up a sizable piece of aquarium space and would dwarf any actual castle you could add.

If Dragons are something you like check out these Dragon Fish Tank Decorations ideas.

Video: Game Of Thrones Castle Aquarium


All the castle aquarium decor ideas here are concepts that you can use to fuel your own designs. You might consider adding some DIY fish tank decorations to enhance store-bought items as well.

My favorite is the ancient rock face castle because there are so many fun things you can do to your tank with this as the focal point.

Your imagination is the only limit in the land of once upon a time.

Jack Dempsey
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